In this case, they are definitely worth it, no contest. Those zooms are very sharp, high quality, stabilized and their weaknesses (CA and distortion) are well corrected by the camera software.

You shoot with an Olympus camera

In this case, the answer is more complex. It depends mainly on your CA tolerence and if you shoot RAW or JPEG.

If you shoot mainly RAW and use softwares like LR, you can correct CA and distortion fairly easily. In this case, those zooms may worth it, if you're willing to spend this money knowing the lenses weaknesses, of course.

If you shoot JPEGS, that's more problematic. In this case, spending 1000$ for a zoom that shows a fairly large amount of CA can be considered as a bit too expensive, but of course, it's a personal opinion, YMMV.

Personally, I shoot RAW+JPEGS, but I'm not CA tolerant, and as I shoot mainly with the EM-5, I'll wait for the Olympus 12-40.